l conspiring to prove one uniform truth. Therefore, a
general theory of petrification or consolidation of mineral bodies must
explain this distinct fact, and not suffer it any longer to remain a
_lusus naturae_.

[Note 36: Mem. de l'Academie Royale des Sciences, an. 1775.]

Let us now consider what it is that we have to explain, upon the
supposition of those concretions being formed from a solution. We have,
first, To understand what sort of a solution had been employed for the
introducing of those various substances; secondly, How those concretions
had been formed from such solutions within those bodies of strata; and,
lastly, How such concretions could have been formed, without any vestige
appearing of the same substance, or of the same operation, in the
surrounding part of the stratum. Whatever may be the difficulty
of explaining those particular appearances by means of fusion and
mechanical force, it is plainly impossible to conceive those bodies
formed in those places by infiltration, or any manner of concretion from
a state of solution.

Naturalists, in explaining the formation of stones, often use a chemical
language which either has no proper meaning, or which will not apply to
the subject of mineral operations. We know the chemical process by which
one or two stony concretions may be formed among bodies passing from
one state to another. When, therefore, a change from a former state of
things in mineral bodies is judged by naturalists to have happened, the
present state is commonly explained, or the change is supposed to have
been made by means of a similar process, without inquiring if this had
truly been the case or not. Thus their knowledge of chemistry has led
naturalists to reason erroneously, in explaining things upon false
principles. It would be needless to give an example of any one
particular author in this respect; for, so far as I have seen, it
appears to be almost general, every one copying the language of another,
and no one understanding that language which has been employed.

These naturalists suppose every thing done by means of solution in the
mineral kingdom, and yet they are ignorant of those solvents. They
conceive or they imagine concretions and crystallizations to be formed
of every different substance, and in every place within the solid body
of the earth, without considering how far the thing is possible which
they suppose. They are constantly talking of operations which could only